I would say that RAID5 is definitely the problem. We have seen the same thing.
Our config is to place the db and log volume on RAID1 (mirror) drives and the storage pools vols on JBOD disks. I was astonished by the performance difference. And this was with hardware RAID5. Paul is absolutely correct: for the larger RAID things (ESS, EMC, etc.), this problem is hidden by the controller. Probably its cache hardware. Kelly J. Lipp STORServer, Inc. 485-B Elkton Drive Colorado Springs, CO 80907 [EMAIL PROTECTED] or [EMAIL PROTECTED] www.storsol.com or www.storserver.com (719)531-5926 Fax: (240)539-7175 -----Original Message----- From: ADSM: Dist Stor Manager [mailto:ADSM-L@;VM.MARIST.EDU]On Behalf Of Seay, Paul Sent: Wednesday, October 23, 2002 4:10 PM To: [EMAIL PROTECTED] Subject: Re: RAID5 in TSM It depends! Not all RAID-5 is created equal. NT software RAID-5 is a dog and for that fact all software RAID-5 solutions are questionable. IBM ESS under the covers RAID-5 is insulated by the controllers in the ESS, so you do not care about it. Paul D. Seay, Jr. Technical Specialist Naptheon Inc. 757-688-8180 -----Original Message----- From: Raghu S [mailto:raghu@;COSMOS.DCMDS.CO.IN] Sent: Wednesday, October 23, 2002 12:31 AM To: [EMAIL PROTECTED] Subject: Re: RAID5 in TSM Paul, keeping TSM database,log and disk storage pool on RAID5 degrades the performance??? Regards Raghu "Seay, Paul" <seay_pd@NAPT To: [EMAIL PROTECTED] HEON.COM> cc: Sent by: Subject: Re: RAID5 in TSM "ADSM: Dist Stor Manager" <[EMAIL PROTECTED] RIST.EDU> 10/22/2002 06:29 AM Please respond to "ADSM: Dist Stor Manager" Are you running compression? Paul D. Seay, Jr. Technical Specialist Naptheon Inc. 757-688-8180 -----Original Message----- From: Raghu S [mailto:raghu@;COSMOS.DCMDS.CO.IN] Sent: Tuesday, October 22, 2002 8:03 AM To: [EMAIL PROTECTED] Subject: RAID5 in TSM Hi, There was a lot of discussion on this topic before.But i am requesting TSM gurus give their comments again. The set up is like this. TSM Server : Windows NT 4.0 SP6, TSM 5.1.0.0 392 MB memory, P III Adaptech Ultra SCSI Hard Disk : Internal Hardware RAID 5: array A : 8.678GB * 3 : 17.356GB data and 8.678 GB parity array B : 35.003 GB * 3 : 70.006GB data and 35.003 GB parity. Both array A and array B are connected to the same channel. OS and TSM 5.1 are installed on array A TSM data base, recovery log and Disk storage pool are installed in array B. Database : 2GB+2GB = 4 GB and mirrored at TSM level on the same array Recovery Log : 500MB + 500 MB = 1 GB and mirrored at TSM level on the same array Disk Storage pool : 10GB+10GB+10GB+10GB+5GB=45GB on array B TSM client: 4.1.2.12 ( Tivoli says 4.1.2.12 is not supported with 5.1 Server. But i could take the backup,archive and restore with this combination ) Number of Clients : 55, all are windows Incremental backup : 1GB/ client/day. backup window : 9AM to 6PM with 50% randamization ( all are in polling mode ) LAN : 100Mbps End of the day only 10 clients could finish the backup.Remaining all are missing or "?" ( in progress ) or failed. Through the entire backup window the CPU load is 100% with dsmsvc.exe holding 98% I tested with various options. I stopped the schedular and fired 3 clients backup manually at the same time.Each client has 1 GB of incremental data. It took three hours to finish the backup. While backing up i observed there was lot of idletime outs of sessions. Network choke is not there. I checked this with FTP. Whats the bottleneck here? Is RAID 5 is creating problems ( DB,log and storage pool all are on the RAID 5 )? I asked the customer to arrange a testing machine without any RAID. I will be getting that in two days.Before going on to the testing i like to know your comments on this. Regards Raghu S Nivas Consultant - TSM DCM Data Systems Ltd New Delhi India.
